Regarding your question, if purity and equality is the goal to reach, the 3rd option should be chosen in my opinion. Boats with a lot of tuning possibilities could maybe find a way to block them before the race starts and thus become "traditional legal' (I don't know if this is feasible, I never saw a modern wooden dinghy. I bought an old boat and do not seek to make it more complex than it is. If I wanted speed, I would have bought a catamaran or even a jetski !
Same feeling when I did archery and stayed away from compound bows, with their pulleys, cams, aiming devices, releasing devices, etc. I went for historic bows, whether early 20th century, medieval or prehistoric.
A fourth solution would eventually be to give a different handicap to different types of dinghies just like in "interseries" races. It would take a few years and a few races but then an honest set of handicap figures would come out and fairness would return.
I'm not a real racer (even if I was thrilled to beat a Vaurien 4 times in Les Settons on Saturday and Sunday !) but I would not like to be beaten due to sailing a different type of boat only.
You know what? In the french sailing federation ratings, a Dinghy 12 is supposed to be slower than a Vaurien:
Code/Group/Name/Crew number/Rating/Race duration Factor
And in a second email Romain wrote me:
To sum up my thoughts, as merging the fleets by deciding a new international specification seems impossible, I would be in favour of giving ratings to dinghys with the classes you mentionned: Dutch (always traditional), Italian tuned wooden boats, even plastic if necessary.
We could even compute a better handicap bonus to boats crewed by 2 compared to single crew. That way, there would be no need to leave people on shore even if the Beaufort is low (and a leaking hull like mine could be bailed and still have a chance to win).
There could be thus "interserie" international races on an equal footing. Local races would still be one-class.
It would give something like this (numbers are fictitious) to multiply the races duration with:
1 Crew 2 crews
Dutch specs 1,0 0,9
Italian specs wood 1,1 1,0
Modern D 12 1,2 1,1
I realize that the tactics would be quite different for an interserie race compared to one class, as the main goal (between different classes) would be to go as fast as possible instead of just being ahead of the next boat.
But I'm not a real tactician, so I could live with that !